[30.15] Coupling of pressure waves to clouds in the Jovian troposphere

P. Gaulme, B. Mosser (Observatoire de Paris)

The receipt for a successful study of the Jovian interior
structure is given by the association of seismology and
precise visible photometry. In this framework, the
micro-satellite project Jovis, presented to the French space
agency (Mosser et al. 2004), is for Jupiter a copy of what
the Europen space mission COROT is for the stars (Baglin et
al. 1998). The Jovian visible flux being dominated by the
albedo map, an accurate analysis of the cloud response to a
seismic wave is needed. Therefore, we have revisited the
propagation of sound waves in the Jovian troposphere, in
order to estimate how they affect the uppest clouds layer,
composed of ammonia ice. First, considering Jupiter as a
mirror, the expected variations of the reflected solar flux
due to the smooth distorsions are about the ppm level for a
50 cm s-1 amplitude wave. Second, introducing
thermodynamics, we determine the phase transitions induced
by the waves in the clouds. These phase changes are linked
to the ice particles growth, and limited by kinetics. A Mie
model (Mishchenko et al 2002) associated to a simple
radiation transfer model allows us to estimate that the
final albedo fluctuations of the cloud perturbed by a
seismic wave can reach the 70-ppm level. This gain of a
factor 70 makes the phenomenon easier to observe and opens
new prospectives for the seismic study of Jupiter : low
amplitude modes, high degrees modes. \vspace{1cm}\\ Baglin
et al. 1998. 185 IAU. Symp. pp. 301. Kyoto. \\ Mosser
et al. 2004. SF2A-2004 pp. 257. EdP-Sciences, Les
Ulis. \\ Mishchenko et al. 2002. Scatt. Abs. Em. Light
Small Particles pp. 158-190. Cambridge University Press.